Water penetration is one of the most significant factors leading to premature failures of structures. One of the most common failure points where water enters a building's envelope is around exterior windows and doors. In conventional constructions, the ability to prevent water intrusion around window and door fenestrations is highly dependent upon the skill of the carpenter constructing the fenestration and the durability and reliability of the various materials used.
In a conventional fenestration construction, there are several separate assemblies that, if not constructed properly, will lead to failure and water intrusion. One area prone to failure, resulting in water intrusion, is the rough opening that is framed into the frame of the exterior wall into which the window is to be installed. The rough opening is essentially comprised of a header, a sill, and a pair of spaced trim studs extending vertically between the header and sill. The rough opening can be considered the base from which the remaining fenestration is built. If the rough opening is not constructed to be perfectly square (for rectangular windows) with an equal sized opening and with the correct opening dimensions for a particular window, the remaining construction becomes more difficult and more likely to fail. Another area prone to failure is the waterproof membrane that is installed around the rough opening on top of the wall's exterior sheeting, and in some applications installed over the nail fin of the window. The waterproof membrane is typically cut into long strips and is layered around the rough opening such that adjacent strips are overlapped with the vertical most layer being on top. The waterproof membrane must be carefully installed to ensure proper alignment with the rough opening and to overlay adjacent waterproof membrane layers. Another area prone to failure is the flashing that is installed along the top of the window once the window has been installed, and in some applications, the sill pan flashing that is installed along the sill of the rough opening before the window is installed.
In addition to the above, another potential problem area includes the surround trim and the sill. If the surround trim and sill is not properly sized and installed correctly, water can be directed to failure prone areas of the fenestration construction. Further, improperly sized and/or installed surround trim and sill assemblies result in a less than desirable appearance. Further, it requires a skilled carpenter to install surround trim and sills on multiple similar fenestrations while maintaining consistency between each fenestration such that each fenestration has the same visual appearance.
Accordingly, it is desirable to have a fenestration construction member which overcomes the disadvantages of the prior art, and provides increased waterproofing by integrating fenestration construction into a unitary, monolithic member that is easily installed by less skilled laborers.